Exposure to chemicals is influenced by associations between the individual’s location and activit... more Exposure to chemicals is influenced by associations between the individual’s location and activities as well as demographic and physiological characteristics. Currently, many exposure models simulate individuals by drawing distributions from population-level data or use exposure factors for single individuals. The Residential Population Generator (RPGen) binds US surveys of individuals and households and combines the population with physiological characteristics to create a synthetic population. In general, the model must be supported by internal consistency; i.e., values that could have come from a single individual. In addition, intraindividual variation must be representative of the variation present in the modeled population. This is performed by linking individuals and similar households across income, location, family type, and house type. Physiological data are generated by linking census data to National Health and Nutrition Examination Survey data with a model of interindiv...
ï‚· Users may download and print one copy of any publication from the public portal for the purpose... more ï‚· Users may download and print one copy of any publication from the public portal for the purpose of private study or research. ï‚· You may not further distribute the material or use it for any profit-making activity or commercial gain ï‚· You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
ABSTRACT Special section introduced with a discussion of how the term bioethics changed from a br... more ABSTRACT Special section introduced with a discussion of how the term bioethics changed from a broad defiintion of life science ethics, including both medical and environmental ethics, to exclusively biomedical ethics. There are indications that the fields are reconverging.
ABSTRACT A comprehensive and interdisciplinary approach to the science and engineering behind und... more ABSTRACT A comprehensive and interdisciplinary approach to the science and engineering behind understanding, measuring, and managing air quality. Sections on pollution control have been reorganized and updated to demonstrate the move from regulation and control approaches to green and sustainable engineering approaches. The fifth edition maintains a strong interdisciplinary approach to the study of air pollution, covering such topics as chemistry, physics, meteorology, engineering, toxicology, policy, and regulation. New material includes near-road air pollution, new risk assessment approaches, indoor air quality, the impact of biofuels and fuel additives, mercury emissions, forecasting techniques, and the most recent results from the National Air Toxics Assessment.
ABSTRACT Substantial variability exists in air pollutant exposures at neighborhood scales. Factor... more ABSTRACT Substantial variability exists in air pollutant exposures at neighborhood scales. Factors driving exposure variability include pollutant source variability, chemical composition of the pollutant mixture, meteorology, layout of the built environment, building dimensions, and human time-activity patterns. States and cities do not typically have sufficient monetary and human resources to perform the saturation sampling necessary to obtain temporally and spatially resolved pollutant concentration data. Moreover, emergency responders may require guidance on safe procedures in the case of an intentional or accidental contaminant release. Thus, short-term high spatiotemporal resolution studies can be valuable for providing insight into the complex relationships between pollutant levels and relevant factors such as meteorology and building dimensions. Scaling relationships derived from such studies may help cities understand spatially resolved estimates of concentration decay using current meteorological and built environment data in the absence of dense contaminant sampling networks. The URBAN 2000, Joint Urban 2003, and Urban Dispersion Program studies held respectively in Salt Lake City, Oklahoma City, and New York City (jointly referred to here as the Urban Dispersion Program, or UDP) were designed and implemented to collect spatiotemporally resolved ambient concentration, personal exposure, and meteorology data. Perfluorocarbon (PFT) tracers were released at several locations within the study sites and then sampled at gridded locations using time-programmable gas capture devices to attain a time-evolving concentration surface. Programmable capture devices were worn by subjects who walked on scripted paths during the campaign. Roof-top and ground-level mean and turbulent wind data were obtained using sonic anemometers and SODAR systems to profile the wind. In this current work, UDP concentration and microscale turbulent wind data were reanalyzed to examine scaling relationships. Street-level PFT concentration time-series were reviewed to find time periods that included a peak and decay. Exponential decay curves were fit to each period, and a characteristic residence time was derived from each model slope. That residence time was nondimensionalized by the ratio of mean wind speed to height of the downwind building bounding the street canyon in which the concentration was measured. SODAR data were used to assess atmospheric turbulence conditions at times concurrent with the concentration decay measurements. Reynolds number and freestream turbulence intensity were calculated from the 15-minute average and standard deviation of velocity. An inverse relationship was observed between the nondimensionalized residence time and turbulence intensity computed from the wind data, although no apparent relationship could be discerned regarding Reynolds number. These data suggest that atmospheric turbulence plays a role in ventilating urban street canyons even within a dense urban environment and that contaminant residence time can be predicted with turbulence intensity data. In addition to providing information on contaminant exposure, these results can provide guidance for emergency response protocols. Validation work is needed at sites with concurrent ambient concentration monitors to determine if trends in concentration can be predicted using this approach and, if so, for which distribution of pollutants such an approach could be applicable in every-day or emergency response scenarios.
Wildfire and Station Wildfire. Of the dozens of wildfires that burned across the State of Califor... more Wildfire and Station Wildfire. Of the dozens of wildfires that burned across the State of California during 2009, two were especially notable due to the size of the fires, loss of life and property. The La Brea fire (August 8-August 22, 2009) began as the result of a propane stove being operated at the site of an illegal marijuana plantation. 1 The Station fire began on August 26, 2009 in the Angeles National Forest. This fire, burning for several weeks, consumed more than 160,000 acres. The fire was fully contained on October 16, 2009. It was the largest wildfire ever recorded for the Angeles National Forest and the 10 th largest fire in California since 1933. 2 These episodic wildfire events in California impacted Las Vegas ambient air quality. As a result of these fires and transport of air pollutants into the Las Vegas urban area, an air quality S3 advisory was issued by Clark County Department of Air Quality and Environmental Management (DAQEM) for smoke from wildfires burning in Southern California from August 13 thru August 16, 2009 (La Brea fire). 3 Air quality advisories were issued by Clark County Department of Air Quality and Environmental Management (DAQEM) for ground-level ozone due to smoke from wildfires burning in Southern California from August 29 thru September 2, 2009 (Station fire). 3 Las Vegas Project Sites. Figure S1 shows a map of the Las Vegas monitoring sites and the location of the city relative to the rest of the United States. Figure S1. Map of Las Vegas monitoring sites. Near-Road Measurements. The Las Vegas near-road study followed a monitoring protocol, which outlined a uniform approach to evaluate the dispersion patterns and contributions
Exposure to chemicals is influenced by associations between the individual’s location and activit... more Exposure to chemicals is influenced by associations between the individual’s location and activities as well as demographic and physiological characteristics. Currently, many exposure models simulate individuals by drawing distributions from population-level data or use exposure factors for single individuals. The Residential Population Generator (RPGen) binds US surveys of individuals and households and combines the population with physiological characteristics to create a synthetic population. In general, the model must be supported by internal consistency; i.e., values that could have come from a single individual. In addition, intraindividual variation must be representative of the variation present in the modeled population. This is performed by linking individuals and similar households across income, location, family type, and house type. Physiological data are generated by linking census data to National Health and Nutrition Examination Survey data with a model of interindiv...
ï‚· Users may download and print one copy of any publication from the public portal for the purpose... more ï‚· Users may download and print one copy of any publication from the public portal for the purpose of private study or research. ï‚· You may not further distribute the material or use it for any profit-making activity or commercial gain ï‚· You may freely distribute the URL identifying the publication in the public portal If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
ABSTRACT Special section introduced with a discussion of how the term bioethics changed from a br... more ABSTRACT Special section introduced with a discussion of how the term bioethics changed from a broad defiintion of life science ethics, including both medical and environmental ethics, to exclusively biomedical ethics. There are indications that the fields are reconverging.
ABSTRACT A comprehensive and interdisciplinary approach to the science and engineering behind und... more ABSTRACT A comprehensive and interdisciplinary approach to the science and engineering behind understanding, measuring, and managing air quality. Sections on pollution control have been reorganized and updated to demonstrate the move from regulation and control approaches to green and sustainable engineering approaches. The fifth edition maintains a strong interdisciplinary approach to the study of air pollution, covering such topics as chemistry, physics, meteorology, engineering, toxicology, policy, and regulation. New material includes near-road air pollution, new risk assessment approaches, indoor air quality, the impact of biofuels and fuel additives, mercury emissions, forecasting techniques, and the most recent results from the National Air Toxics Assessment.
ABSTRACT Substantial variability exists in air pollutant exposures at neighborhood scales. Factor... more ABSTRACT Substantial variability exists in air pollutant exposures at neighborhood scales. Factors driving exposure variability include pollutant source variability, chemical composition of the pollutant mixture, meteorology, layout of the built environment, building dimensions, and human time-activity patterns. States and cities do not typically have sufficient monetary and human resources to perform the saturation sampling necessary to obtain temporally and spatially resolved pollutant concentration data. Moreover, emergency responders may require guidance on safe procedures in the case of an intentional or accidental contaminant release. Thus, short-term high spatiotemporal resolution studies can be valuable for providing insight into the complex relationships between pollutant levels and relevant factors such as meteorology and building dimensions. Scaling relationships derived from such studies may help cities understand spatially resolved estimates of concentration decay using current meteorological and built environment data in the absence of dense contaminant sampling networks. The URBAN 2000, Joint Urban 2003, and Urban Dispersion Program studies held respectively in Salt Lake City, Oklahoma City, and New York City (jointly referred to here as the Urban Dispersion Program, or UDP) were designed and implemented to collect spatiotemporally resolved ambient concentration, personal exposure, and meteorology data. Perfluorocarbon (PFT) tracers were released at several locations within the study sites and then sampled at gridded locations using time-programmable gas capture devices to attain a time-evolving concentration surface. Programmable capture devices were worn by subjects who walked on scripted paths during the campaign. Roof-top and ground-level mean and turbulent wind data were obtained using sonic anemometers and SODAR systems to profile the wind. In this current work, UDP concentration and microscale turbulent wind data were reanalyzed to examine scaling relationships. Street-level PFT concentration time-series were reviewed to find time periods that included a peak and decay. Exponential decay curves were fit to each period, and a characteristic residence time was derived from each model slope. That residence time was nondimensionalized by the ratio of mean wind speed to height of the downwind building bounding the street canyon in which the concentration was measured. SODAR data were used to assess atmospheric turbulence conditions at times concurrent with the concentration decay measurements. Reynolds number and freestream turbulence intensity were calculated from the 15-minute average and standard deviation of velocity. An inverse relationship was observed between the nondimensionalized residence time and turbulence intensity computed from the wind data, although no apparent relationship could be discerned regarding Reynolds number. These data suggest that atmospheric turbulence plays a role in ventilating urban street canyons even within a dense urban environment and that contaminant residence time can be predicted with turbulence intensity data. In addition to providing information on contaminant exposure, these results can provide guidance for emergency response protocols. Validation work is needed at sites with concurrent ambient concentration monitors to determine if trends in concentration can be predicted using this approach and, if so, for which distribution of pollutants such an approach could be applicable in every-day or emergency response scenarios.
Wildfire and Station Wildfire. Of the dozens of wildfires that burned across the State of Califor... more Wildfire and Station Wildfire. Of the dozens of wildfires that burned across the State of California during 2009, two were especially notable due to the size of the fires, loss of life and property. The La Brea fire (August 8-August 22, 2009) began as the result of a propane stove being operated at the site of an illegal marijuana plantation. 1 The Station fire began on August 26, 2009 in the Angeles National Forest. This fire, burning for several weeks, consumed more than 160,000 acres. The fire was fully contained on October 16, 2009. It was the largest wildfire ever recorded for the Angeles National Forest and the 10 th largest fire in California since 1933. 2 These episodic wildfire events in California impacted Las Vegas ambient air quality. As a result of these fires and transport of air pollutants into the Las Vegas urban area, an air quality S3 advisory was issued by Clark County Department of Air Quality and Environmental Management (DAQEM) for smoke from wildfires burning in Southern California from August 13 thru August 16, 2009 (La Brea fire). 3 Air quality advisories were issued by Clark County Department of Air Quality and Environmental Management (DAQEM) for ground-level ozone due to smoke from wildfires burning in Southern California from August 29 thru September 2, 2009 (Station fire). 3 Las Vegas Project Sites. Figure S1 shows a map of the Las Vegas monitoring sites and the location of the city relative to the rest of the United States. Figure S1. Map of Las Vegas monitoring sites. Near-Road Measurements. The Las Vegas near-road study followed a monitoring protocol, which outlined a uniform approach to evaluate the dispersion patterns and contributions
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